Introduction
  • Epidemiology
    • Gun shot wounds represent the second-leading cause of death for youth in United States.
  • Pathoanatomy
    • wounding capability of a bullet directly related to its kinetic energy  
    • damage caused by
      • passage of missile
      • secondary shock wave
      • cavitation
    • exponential increase in injury with increasing velocity and efficient energy transfer
    • fractures may be caused even without direct impact 
  • Associated conditions
    • lead intoxication (plumbism) 
      • may be caused by intra-articular missile
      • systemic effects include
        • neurotoxicity
        • anemia
        • emesis
        • abdominal colic
    • GSW to hip and acetabulum are most commonly associated with bowel perforation > vascular injury > urogenital injuries 
Classification
  • Low velocity  
    • muzzle velocity <350 meters per second or < 2,000 feet per second
    • most handguns except for magnums 
    • wounds comparable to Gustillo-Anderson Type I or II
  • Intermediate velocity 
    • muzzle velocity 350-500 meters per second
    • shotgun blasts
      • highly variable depending on distance from target
      • can reflect wounding potential of high velocity firearms from close range (less than 21 feet) or multiple low velocity weapons
      • wound contamination/infection with close range injuries due to shotgun wadding
      • wounding potential depends on 3 factors
        • shot pattern
        • load (size of individual pellet)
        • distance from target
  • High velocity 
    • muzzle velocity >600 meters per second or >2,000 feet per second
    • military (assault) and hunting rifles
    • wounds comparable to Gustillo-Anderson Type III regardless of size
    • high risk of infection
      • secondary to wide zone of injury and devitalized tissue
Presentation
  • Symptoms
    • pain, deformity
  • Physical exam
    • perform careful neurovascular exam
    • clinical suspicion for compartment syndrome
      • secondary to increased muscle edema from higher velocity wounds
    • examine and document all associated wounds 
      • massive bone and soft tissue injuries occur even with low velocity weapons  
Evaluation
  • Radiographs
    • obtain to identify bone involvement and/or fracture pattern 
  • CT scan
    • identify potential intra-articular missile 
    • detect hollow viscus injury that may communicate with fracture
      • high index of suspicion for pelvis or spine fractures given increased risk of associated bowel injury
Treatment General
  • Nonoperative
    • local wound care
      • indications
        • low velocity GSW with no bone involvement and clean wound edges
    • local wound care, tetanus +/- short course of oral antibiotics   
      • indications
        • low-velocity injury with no bone involvement or non-operative fractures
      • technique
        • primary closure contraindicated
        • antibiotic use controversial but currently recommended if wound appears contaminated
  • Operative
    • treatment of other non-orthopedic injuries
      • for trans-abdominal trajectories, laparotomy takes precedence over arthrotomy 
    • ORIF/external fixation
      • indications
        • unstable/operative fracture pattern in low-velocity gunshot injury
      • technique
        • treatment dictated by fracture characteristics similar to closed fracture without gunshot wound
        • stabilize extremity with associated vascular or nerve injuries   
        • stabilize soft tissues in high velocity/high energy gunshot injuries  
          • grossly contaminated/devitalized wounds managed with aggressive debridement per open fracture protocol
    • arthrotomy
      • indications
        • intra-articular missile
          • may lead to local inflammation, arthritis and lead intoxication (plumbism) 
        • transabdominal GSW   
GSW to Hand/Foot
  • Nonoperative
    • antibiotics
      • indications
        • gross contamination
        • joint penetration
        • extent of contamination unclear
  • Operative
    • surgical debridement +/- ORIF/external fixation
      • indications
        • articular involvement
        • unstable fractures
        • presentation 8 or more hours after injury
        • tendon involvement
        • superficial fragments in the palm or sole
GSW to Femur
  • Operative
    • intramedullary nailing 
      • indications
        • diaphyseal femur fracture secondary to low-velocity gunshot wound  
        • superficial wound debridement and immediate reamed nailing
        • similar union and infection rates to closed injuries
    • external fixation
      • indications
        • high-velocity gunshot wounds or close range shotgun blasts
        • stabilize soft tissues and debride aggressively
        • associated vascular injury
        • temporize extremity until amenable to intramedullary nailing
GSW to Spine
  • Nonoperative
    • broad spectrum IV antibiotics for 7-14 days 
      • indications
        • gunshot wounds to the spine with associated perforated viscus  
          • bullets which pass through the alimentary canal and cause spinal cord injuries do not require surgical removal of the bullet
  • Operative
    • surgical decompression and bullet fragment removal
      • indications 
        • when a neurologic deficit is present that correlates with radiographic findings of neurologic compression 
          • a retained bullet fragment within the spinal canal in patients with incomplete motor deficits is a relative indication for surgical excision of the fragment